So far, for example, Patent Document 1 discloses a variable valve operating apparatus for an internal combustion engine in which a cam carrier provided with two kinds of cams is provided for each cylinder, and, during a base-circle section of the two kinds of cams, the cam carrier is moved in the axial direction with respect to a cam main-shaft which is rotated, so that valve drive cams for each cylinder are switched. To be more specific, in this conventional variable valve operating apparatus, guide grooves which are formed into a helical shape are provided respectively in both ends of the outer peripheral surface of each cam carrier. Moreover, an electric actuator, which drives a drive pin to be inserted into or removed from the guide groove, is provided for each guide groove. Furthermore, the above-described conventional variable valve operating apparatus is applied with respect to a straight four-cylinder engine.
According to the above-described conventional variable valve operating apparatus, the cam carrier is displaced with respect to the axial direction thereof by engaging the drive pin to which the axial position of the camshaft is fixed with the guide groove. As a result of this, the valve drive cams for each cylinder are switched, and the lift amounts of valves can be therefore changed.
Moreover, for example, Patent Document 2 discloses a diesel engine equipped with a variable valve operating apparatus for changing operating characteristics of an intake valve. This conventional variable valve operating apparatus includes a gas pressure type actuator using a gas pressure. This gas pressure type actuator moves one control rod (link shaft) and a control plate (link arm) for each cylinder coupled therewith in the axial direction thereof, and thereby the operating characteristics of the valves for all cylinders are collectively changed.
Including the above mentioned document, the applicant is aware of the following documents as a related art of the present invention.